I changed to 4349 too, and worked OK. But I'd like to say that the original problem (related, of course, to the driver) is an error in the refresh handling. I tried to plug an external monitor (21") and worked Ok with 4496 and 4363 (glxinfo showed direct rendering usging driver nvidia).
Why is that working with an older version and not with the newer ones?!?!?
And of course that bars in a resolution different to 1280 are annoying :P
Thank you for the change of driver idea...